Threaded pipe
A threaded pipe is a
Tapered threads
The threaded pipes used in some plumbing installations for the delivery of gases or liquids under pressure have a tapered thread that is slightly
Especially precise threads are known as "dry fit" or "dry seal" and require no sealant for a gas-tight seal. Such threads are needed where the sealant would contaminate or react with the media inside the piping, e.g., oxygen service.
Tapered threaded fittings are sometimes used on plastic piping. Due to the wedging effect of the tapered thread, extreme care must be used to avoid overtightening the joint. The overstressed female fitting may split days, weeks, or even years after initial installation. Therefore many municipal plumbing codes restrict the use of threaded plastic pipe fittings.
Both
Straight threads
Pipes may also be threaded with cylindrical threaded sections, in which case the threads do not themselves provide any sealing function other than some labyrinth seal effect, which may not be enough to satisfy either functional or code requirements. Instead, an O-ring seated between the shoulder of the male pipe section and an interior surface on the female, provides the seal.
See also
- AN thread
- British Standard Pipe thread (BSP)
- Buttress thread
- Fire hose thread
- Garden hose thread
- National pipe thread (NPT)
- Nipple (plumbing)
- O-ring boss seal
- Panzergewinde (steel conduit thread)
- Piping
- Plumbing
- Screw thread
- Tap and die
- Thread angle
- United States Standard thread
External links
- NPT Vs. NPTF Taper Pipe Threads
- Newman Tools Inc. and J.W. WINCO, INC. show the BSP or ISOpipe thread.